Lelisa Desisa of Ethiopia crosses the finish line to win the men's division of the 2013 Boston Marathon Monday. He finished in 2:10:22, 5 seconds ahead of Micah Kogo of Kenya. Elise Amendola AP

On Patriots Day, Rita Jeptoo of Kenya crosses the finish line to win the women's division of the 117th Boston Marathon. Her time of 2:26:25 was nearly 30 seconds faster than Meseret Hailu of Ethiopia. Jim Rogash Getty Images

American Shalane Flanagen (third from left) runs with Rita Jeptoo of Kenya near the 19 mile marker during the 2013 Boston Marathon. Jeptoo won in 2:26:25. Flanagan was fourth in 2:27:08. Greg M. Cooper-USA TODAY Sports

Ana Dulce Felix of Portugal leads near the 19 mile marker during the Boston Marathon. She fell off the pace and finished ninth. Greg M. Cooper-USA TODAY Sports

Runners start the 117th running of the Boston Marathon, in Hopkinton, Mass., Monday. The race started with 26 seconds of silence in honor of the victims of the Sandy Hook Elementary School shootings. Stew Milne AP

Yolanda Caballero of Colombia runs alone at the 12-mile mark on the Boston Marathon course in Wellesley, Mass., Monday. She was among a group of four who broke away early before pulling ahead of the pack. Michael Dwyer AP

The elite men start the 117th running of the Boston Marathon, in Hopkinton, Mass., Monday. Stew Milne AP

Runners gather around a portable heater in the athletes village prior to the start of the Boston Marathon. A field of 27,000 athletes were entered in the race. Stew Milne AP

Dick Hoyt, right, and his son, Rick, stand next to a statue honoring them near the start of the Boston Marathon Monday. Dick, 72, has pushed his son in 31 Boston Marathons. Stew Milne AP

Defending champion Shirley Reilly, left, gets her wheelchair into position prior to the start of the wheelchair division of the 117th running of the Boston Marathon, in Hopkinton, Mass., Monday. Stew Milne AP

Runners start the 117th running of the Boston Marathon, in Hopkinton, Mass., Monday. The temperature was 48 degrees at the start. Stew Milne AP